Laser processing method

• US RE37,993 E1
• Filed: 07/02/1998
• Issued: 02/18/2003
• Est. Priority Date: 10/21/1992
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Zhang, Hongyong
• Primary Examiner(s): Scott, Jr., Leon
• Application Number:
  US09/109,157
• Time in Patent Office: 1,692 Days
• Field of Search: 372/25, 372/7, 372/87, 372/109, 372/98, 372/69, 372/92, 372/66, 372/70
• US Class Current: 372/25
• CPC Class Codes: B23K 26/06 Shaping the laser beam, e.g. by masks or multi-focusing
• CPC Class Codes: B23K 26/064 by means of optical elements, e.g. lenses, mirrors or prisms
• CPC Class Codes: B23K 26/0643 comprising mirrors
• CPC Class Codes: B23K 26/0648 comprising lenses
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/10038 Amplitude control
• CPC Class Codes: H01S 3/104 in gas lasers
• CPC Class Codes: H01S 3/2256 KrF, i.e. krypton fluoride is comprised for lasing around 248 nm
• CPC Class Codes: H01S 3/2316 Cascaded amplifiers
• CPC Class Codes: H01S 3/2383 Parallel arrangements

Abstract

Method of processing, e.g., laser annealing, objects such as semiconductor devices with pulsed lasers with high production yield and high reproducibility so as to obtain good characteristics stably. The pulse width of the irradiated pulse beam is set to more than 30 nsec to stabilize the processing. To achieve a pulse width exceeding 30 nsec, plural lasers are connected in series or in parallel and excited successively.

Claims

1. A laser processing method comprising the steps of:

generating a laser pulse from a laser, said laser pulse having a pulse width duration w; and

amplifying said laser pulse by the step of activating a laser amplifier at a time t after generating step, wherein said time t is between about 0.5 times said pulse width duration w and 5.0 times said pulse width duration w; and

processing an object with said laser pulse emitted from said laser amplifier.

2. The method of claim 1 wherein said processing step further comprises the step of irradiating said object with said laser pulse.

3. The method of claim 1 wherein said object is a semiconductor which is substantially amorphous.

4. The method of claim 1 wherein said object is a substantially amorphous silicon semiconductor containing at least 1 volume % of hydrogen.

5. The method of claim 1 further comprising the step of activating said laser by a pulse generated by a trigger pulse generation means connected to said laser and said laser amplifier.

6. The method of claim 1 further comprising the step of activating said laser amplifier by a pulse generated by a trigger pulse generation means connected to said laser and said laser amplifier.

7. A laser processing method comprising the steps of:

generating a laser pulse from a laser, said laser pulse having a pulse width duration w;

amplifying said laser pulse by activating a laser amplifier at a time t after said generating step, wherein said time t is between about 0.5 times said pulse width duration w and 5.0 times said pulse width duration w; and

processing an amorphous silicon film containing hydrogen at a concentration of 10 to 30% with said laser pulse.

8. The method of claim 7 wherein the irradiated laser pulse has one peak of a pulse height thereof which is the same as that of the laser pulse as generated from said laser device, and has another peak of a pulse height following said one peak wherein the pulse height of said one peak is from about 0.25 to 0.50 times the pulse height of said another peak.

9. The method of claim 8 wherein said another peak is formed by said amplifying step.

10. The method of claim 7 further comprising the step of activating said laser by a pulse generated by a trigger pulse generation means connected to said laser and said laser amplifier.

11. The method of claim 7 further comprising the step of activating said laser amplifier by a pulse generated by said trigger pulse generation means connected to said laser and said laser amplifier.

12. The method of claim 7 further comprising the step of improving crystallinity of said silicon film by irradiating said silicon film with said laser pulse.

13. A laser processing method comprising the steps of:

generating a laser pulse from a laser, said laser pulse having a pulse width duration w;

amplifying said laser pulse by activating a laser amplifier at a time t after said generating step, wherein said time t is between about 0.5 times said pulse width duration w and 5.0 times said pulse width duration w; and

processing a silicon oxide film containing carbon at a concentration of 0.1 to 1% with said laser pulse.

14. The method of claim 13 further comprising the step of forming said silicon oxide film by chemical vapor deposition using tetraethoxysilane.

15. The method of claim 13 wherein said processing step comprises the step of desorbing the carbon in said silicon oxide film.

16. The method of claim 13 further comprising the step of activating said laser by a pulse generated by said trigger pulse generation means connected to said laser and said laser amplifier.

17. The method of claim 13 further comprising the step of activating said laser amplifier by a pulse generated by said trigger pulse generation means connected to said laser and said laser amplifier.

18. A laser processing method comprising the steps of:

19. The laser processing method according to claim 18 wherein said semiconductor film comprises amorphous silicon.

20. The laser processing method according to claim 18 wherein said laser is an excimer laser.

21. The laser processing method according to claim 20 wherein said excimer laser is selected from Ar₂ laser, Kr₂ laser, Xe₂ laser, ArF laser, KrCl laser, KrF laser, XeCl laser and XeF laser.

22. The laser processing method according to claim 18 wherein said semiconductor film comprises amorphous silicon containing hydrogen at 1 volume % or more.

23. The laser processing method according to claim 18 wherein the irradiated laser pulse has one peak of a pulse height thereof which is the same as that of the laser pulse as generated from said laser device, and has another peak of a pulse height following said one peak wherein the pulse height of said one peak is from about 0.25 to 0.50 times the pulse height of said another peak.

24. A laser processing method comprising the steps of:

25. The laser processing method according to claim 24 wherein said semiconductor film comprises amorphous silicon.

26. The laser processing method according to claim 24 wherein said laser is an excimer laser.

27. The laser processing method according to claim 26 wherein said excimer laser is selected from Ar₂ laser, Kr₂ laser, Xe₂ laser, ArF laser, KrCl laser, KrF laser, XeCl laser and XeF laser.